A study on boiling heat transfer in three-phase circulating fluidized bed

A vapor-liquid-solid circulating fluidized bed, which is a new type of evap oration boiling means for enhancing heat transfer and preventing fouling, i s presented. Experiments were conducted in a 39 mm diameter 2.0 m high stai nless steel column, in which the heat transfer coefficient was measured for different superficial velocities, pressure of the heating stream, particle concentration and kinds of particles. The experimental results show that t he boiling heat transfer coefficient is enhanced and is about 1.5-2.0 times that of vapor-liquid two-phase flow. The heat transfer coefficient increas ed with increase in the pressure of the heating stream, but it exhibited a local minimum value with increasing liquid velocity. (C) 2000 Elsevier Scie nce S.A. All rights reserved.